The Senate approved Senate Concurrent Resolution 3.
What is a concurrent resolution?
A concurrent resolution instructs both chambers of Congress to perform some action. Like a law, it must be approved by both chambers to come into effect. However, it will not go to the President for signing. It is a tool to help organize the work of Congress.
In this case, the resolution proposes an outline for the FY2017 budget.
What's special about it?
There is nothing special about the budget figures. However, in the "Reserve Funds" section it allows budget committee chairs to alter budget allocations. They can only do this for healthcare-related appropriations, and only if it does not increase the deficit (meaning that without any other shenanigans, they can only decrease funding).
Why does this matter? The Senate budget chair is Mike Enzi, Republican from Wyoming. The House budget chair is Diane Black, Republican from Tennessee.
Suppose the Senate subcommittee recommends $600 billion for healthcare allocations. Mike Enzi, as Chair of the Budget committee, can unilaterally reduce that amount and pass it on to the Senate floor for debate.
Now, before that amount becomes the budget it must be approved on the Senate floor, the House floor, if there are any differences a joint committee will have to hammer them out, and eventually the President will have to sign them. However, this resolution gives a lot of power to the Republican legislators to set the terms of the debate around healthcare policy.